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A meta-analysis was performed with the aim to identify factors with a relevant influence on the expression of clinical postweaning multisystemic wasting syndrome (PMWS) under experimental conditions. Data from 44 studies were included in the analysis. Several variables were studied: number of pigs in the experiment, intake of colostrum, serological status against porcine circovirus type 2 (PCV2), strain of PCV2 used for inoculation, the route and dose of inoculation, and use of potential triggering factors (such as co-infections, vaccinations, or immunomodulator products). Multiple correspondence analysis and log-linear regression methods were used to establish the relationships between the studied variables and the number of PCV2 infected pigs that developed PMWS. Based on the results of the meta-analysis, the most successful animal experiment aimed to develop PMWS should include: (1) colostrum-deprived pigs, (2) age of inoculation below 3 weeks, (3) high doses of PCV2 inoculum, (4) PCV2 strain from genotype 1, and (5) co-infection with another swine pathogen as a triggering factor. 相似文献
995.
Bean MG Skeríkova A Bonner TH Scholz T Huffman DG 《Journal of aquatic animal health》2007,19(2):71-76
Bothriocephalus acheilognathi is an introduced tapeworm in North America often reported as a serious ecological threat to native fishes. In this paper, we report the first record of B. acheilognathi in the Big Bend region of the Rio Grande in Texas (known as the Río Bravo del Norte in Mexico). Identification of B. acheilognathi was confirmed by morphologic and genetic techniques (sequences of ITS2 and V4-18S rRNA genes). Its prevalence was 27% and its intensity ranged from 1 to 5 individuals in a January 2006 collection of 115 red shiners Cyprinella lutrensis. In addition, it was found in the Tamaulipas shiner Notropis braytoni, a Rio Grande endemic and a new host record. The occurrence of B. acheilognathi might have negative ecological impacts on endemic fishes in the Rio Grande. Several of the fishes that could serve as definitive hosts are of conservation concern. Its occurrence also might affect the success of reintroducing the Rio Grande silvery minnow Hybognathus amarus, which is federally listed as endangered, in this portion of the Rio Grande. 相似文献
996.
Elizabeth A. Moore John F. Munsell A. L. Tom Hammett Keith M. Moore 《Agroforestry Systems》2014,88(4):735-752
Pressure on natural resources and local infrastructure often increase in areas of refugee settlement, and food and health security can decline as a result. Agroforestry is the use of trees and crops and/or livestock in the same farming system to achieve production and conservation objectives. These polycultures can help improve food security in refugee settlement areas by rendering diverse products while increasing conservation in the face of augmented population pressure. In the past 10 years, 90,000 Central African Republic refugees have crossed into Cameroon and settled in hundreds of villages. This study focused on agroforestry preferences among refugees and host-nationals in six villages in the Adamaoua Region of Cameroon. One-hundred and twenty-two community members participated in the study. Visual methods were used to quantify preferences for eight agroforestry practices and tested for statistically significant differences across gender, ethnicity, and status as refugee or Cameroonian. There were differences in practice preferences as well as preferences for implementation in a group or as a family. Most differences were between refugees and Cameroonians. Refugees were more likely to prefer practices that help meet basic needs and also more likely to prefer group implementation. Open-ended comments also were analyzed to contextualize quantitative results. Overall, results suggest that agroforestry preferences in refugee settings may relate to a greater degree on social class and experience rather than gender or ethnicity. Results also indicate common ground in that refugees and host nationals are likely to share many preferences. 相似文献
997.
This communication is a review over the major market and technical challenges and opportunities for nanocellulosic materials on a large scale but in low-to-medium-end markets. Basically, the potential use of nanocellulose as a wet-end strength additive in papermaking has been known for decades, but not come into operation because of the high-energy costs of producing these materials. Cost performance compared to starch derivatives is one challenge, and the other is to design suitable dewatering/retention aid systems. Other paper applications are as a surface-sizing agent and as a barrier coating material. Major challenges are associated with the high viscosity of nanocellulosic materials and how to apply the nanocellulose in order to obtain good surface coverage. There are several opportunities in the nanocomposite markets. The packaging sector together with the automotive sector and the building sector constitute large potential markets. Challenges are related to the mixing of hydrophobic and hydrophilic materials so that a good dispersion of nanocellulose is obtained. Scaling up of nanocellulose production processes and procedures for nanocomposite manufacturing in order to obtain price–performance in the various applications remains, as expected, the largest challenge 相似文献
998.
Social networks play an important role in the communication of information among forest owners and how owners process that information in making land management decisions. This article examines variations in the social network characteristics of family forest owners using survey data and interviews with 42 owners in south-central Indiana. We examine how network structure and content vary by harvesting activity, information sources, ownership attributes, sociodemographic characteristics, and location. Quantitative measures of network size and diversity, along with a qualitative understanding of network content and function are discussed and compared for active and passive forest managers. We find that active managers (people who had a recent timber harvest) had at least twice as many social ties related to forest management compared to passive managers, particularly after accounting for parcel ownership size, forest area, and total landholding size. Learning and service were the main functions of these networks, with learning being the most frequently cited reason for talking to others regardless of the management profile of forest owners. The study contributes to a growing interest in mixed-methods approaches to network studies and research on social networks in private forestry. 相似文献
999.
L. Pérez J.F. Asturiano S. Martínez A. Tomás L. Olivares E. Mocé R. Lavara J.S. Vicente M. Jover 《Fish physiology and biochemistry》2003,28(1-4):221-222
Looking for good sperm diluting media, physio-chemical parameters and ionic composition of the eel seminal plasma were studied in relation with sperm motility. 相似文献
1000.
Tom Hansen 《Aquaculture (Amsterdam, Netherlands)》1985,46(4):275-285
Groups of sea trout (Salmo trutta) eggs were hatched in a Californian hatching system with and without an astro-turf artificial substrate, and were later transferred to separate feeding units. Alevins reared in astro-turf absorbed their yolk faster and more efficiently than alevins reared on a flat screen, an effect which is probably caused by high activity stress in the flat-screened system. Probably due to higher yolk reserves, the fry hatched without astro-turf grew faster than the fry reared with astro-turf during the first periods of feeding. Later this was reversed, giving the astro-turf-reared alevins the highest growth rate. The flat-screen-reared alevins/fry suffered higher mortalities during the experiment and the mortalities were clearly size dependent. These results have consequences both for intensive culture and stocking programmes since the traditional hatching systems both reduce growth and the chance of survival of the fry. 相似文献